Pneumatic-despatch-tube apparatus.



A. W. PEARSALL.

PNEUMATIC DESPATGH TUBE APPARATUS.

APPLIOATION FILED AUG. 20, 1908.

- Patented Sept. 23, 1913.

2 BHEETB-SHEET 1.

ccLuMuIA I'LANOORAPH cm, WASH ING'YON, u. M

A. W. PEARSALL. PNEUMATIC DBSPATGH TUBE APPARATUS.

APPLICATION rum) 116.20, 1908.

1,073,867. Patented Sept. 23, 1913.

2 SHEETS-11231 2.

COLUMBIA PLANOORAP" C ,WI\SIIINDTON, u. c.

UITE STATES UFFICE.

ALBERT W. PEARSALL, F LOWELL, MASSACHUSETTS, ASSIGNOR TO THE LAMSON COMPANY (FORMERLY LAMSON CONSOLIDATED STORE SERVICE COMPANY), OF BOSTON, MASSACHUSETTS, A CORPORATION OF NEW JERSEY.

PNEUMATIC-DESPATCH-TUBE APPARATUS.

To all whom it may concern:

Be it known that I, ALBERT l/V. PEARSALL, of Lowell, in the county of Middlesex and State of Massachusetts, have invented certain new and useful Improvements in Pneumatic-Despatch-Tube Apparatus, of which the following is a specification.

My invention relates to improvements in pneumatic despatch tube apparatus and particularly to the all-sealed vacuum system wherein a vacuum is maintained and air is admitted through a time-controlled valve located at the be1l-mouth or terminal air inlet for driving carriers therethrough. Means are provided for controlling the closure of said valve to limit the flow of air to the interval necessary for the transmission and delivery of the carriers.

The object of this invention is to simplify the construction of such systems and render the same more eflicient and practical.

In the accompanying drawings are illustrated different forms of construction embodying this invention in which Figure 1 is a diagram of an all-sealed pneumatic tube system showing the location of the controlling mechanism operatively connected therewith. Fig. 2 is an enlarged sectional view of the controlling mechanism showing the normal or closed position of the same. Fig. 3 is a similar view to Fig. 2 showing the position of the parts when a carrier is despatched at the bell-mouth or center station. Fig. 4 is a modification showing means operated by the carrier upon its insertion into the bell-mouth for controlling the action of the air-valve. Figs. 5 and 6 are enlarged detail views of the spring mechanism for operating the bell-crank connected with the diaphragm.

Like characters of reference refer to like parts throughout the several views.

Referring to Fig. 1, 2 is a tube for the transmission of carriers connecting the cen tral station C with the discharge terminal 3 controlled by the usual delivery valve 4 at the substation S. 5 is a tube for the return of carriers and connects the terminal 3 with the discharge terminal 6 located at the cen tral station C, and controlled by the ordinary delivery valve 7. 9 is an exhaust tube connecting the terminal 6 with the usual vacuum drum 10 wherein a vacuum is constantly maintained. 8 is the usual despatch- Specification of Letters Patent.

Application filed August 20, 1908.

Patented Sept. 23,1913.

Serial No. 449,507.

ing inlet located at the sub-station S, for insorting carriers into the transmission tube 5. 1 is a bell-mouth or terminal air inlet located in the casing 11 which is connected with the transmission tube 2 at the central station 0 and is adapted to receive carriers for despatch through said tube 2. 12 is an air valve pivoted at 13 in the casing 11 and is normally held closed by the free end of a bell crank lever 1 1 pivoted at 15 within a lower chamber of said casing 11, the opposite end of said lever being connected by a link 16 with the stem of a diaphragm 17 mounted between said casing 11 and a diaphragm cap 18 suitably secured thereto. On the pivot 15 of the bell-crank lever 14 is a spring 15 (Figs. 5, G) that normally tends to move the bell-crank lever to the position shown in Fig. 2. One end of the spring 1? is fast on the pivot 15, and the other end ongages the annular rack 15* fast to the Vail of the shell 11. By adjusting the engagement of the spring with the annular rack the tension of the spring can be regulated and consequently the force of action of the bell-crank lever 14-. The diaphragm 17 and its connections form a pneumatic motor for controlling an d actuating the valve 12. The diaphragm 17 is in communication on one side through a chamber 19 with the vacuum normally maintained in the transmission tube 2 and the casing 11 of the inner side of the air-valve 12. 20 is a sub-air inlet communicating with the chamber 19 at one end and at the opposite end is normally closed by a valve 21 pivoted thereto at 22 and retained in closed position by a spring 24 is a trigger attached to said valve for normally operating the same. The chamber 25 be tween diaphragm l7 and cap 18 has an airoutlet 26 controlled by an organ or check valve 27 which permits the escape of air from said chamber but prevents the admission of air thereto. 28 is an air-inlet conmeeting the chamber 25 with the atmosphere and is restricted by the timing valve 29. 30 is a wind gate or restrietor pivoted at 31 in the casing 11. and is adapted to retard the passage of air through the bell-mouth 1 when the valve 12 is open, to maintain a sufficient vacuum to operate the diaphragm 17. A spring 31 on the pivot 31 normally holds the restrictor 30 in a raised position, as shown in Fig. 2.

In the modification (see Fig. 4) the valve 21 is connected with and operated by the restrictor upon the insertion of a carrier into the bell-mouth 1.

The operation of the device is as follows :In despatohing a carrier from the central station C to the sub-station S, the

operator inserts a carrier into the bell-mouth 1 and pressesthe trigger 2d, admitting air through the tube '20, and destroying the vacuum in the chamber 19, thereby releasing the diaphragm 17 and permitting the same to be moved backward by means of a spring 15. The air in the chamber 25 escapes through the opening 26 controlled by the organ valve 27. Simultaneous with the movement of the diaphragm 17 the free end of bell-crank lever 14 moves out of engagement with the valve 12 permitting the same to open to the position shown in Fig. 3 by the inrush of air through the bell-mouth 1. The operator releases the trigger 24, closing the tube 20 and the air entering the bellm-outh 1 drives the carrier through the transmission tube 2 toward the sub-station S. The carrier having passed over the restricter 30, the same is returned to normal position by a uitable spring 31 located on the pivot 31 and retarding the passage of air through the bell-mouth 1 forms a vacuum in the chamber 19 suflicient to urge the diaphragm 17 gradually outward, the move ment of the same being timed and controlled by the air entering the chamber 25 through the restricted inlet 28. Thet'ree end of the bell crank 14 engages the valve 12 during the movement of said diaphragm 17, gradually closing said valve so that by the time the carrier has delivered at sub-station S said valve is entirely closed, cutting OK the flow of air through the bell-mouth 1. The timing valve 29 may be adjusted to restrict the inlet 28 to secure the proper interval of closure of the valve 12. in despatching a carrier from the sub-station S to the central station C the operator opens the inlet 8, inserts the carrier, then closing said inlet. lhe opening of said inlet destroys the vacuum in the transmission tube 2 and chamber 19, releasing the diaphragm 1'7 and in the manner heretofore described opening the valve 12, admitting air through the bellmouth 1 which drives the carrier through the tube 2 toward the central station C. VI hen the inlet 8 at the sub-station has been closed, the restrictor'30 acts to-it'orm a partial vacuum which operates the diaphragm '17 in a manner identical with that heretofore described, causing the valve 12 to close by the time the carrier has delivered at station 0, cutting off the flow of air through the bell-mouth 1.

In the modification shown in Fig. 4: the

insertion of the carrier into the bell-mouth 1 depresses the restrictor 30, thereby opening the valve 21, admitting air through the tube 20 in chamber 19, causing the mecha- ,nism to operate in a manner hereinbefore ;described. After the carrier has passed over the restrictor 3O the same is returned to normal position by spring 23, closing the valve 21 Having thus described my invention and set forth a construction embodying the same, what I claim as new and desire to secure by Letters Patent of the United States, is:

1. In pneumatic despatch tube apparatus, a carrier transmission tube provided with a mouth to receive carriers and to admit outside air, a valve located in the transmission tube adjacent to its mouth to control the mission of outside air to the tube,said valve being movable in the direction. of the air flowing in through said mouth, when being opened, means for exhausting air from the transmission tube, a chamber communicating directly with the transmission tube inside of the valve so that the pressure in the chamber will vary with the pressure in the tube, means for causing a fluctuation of pressure in the chamber, and a pneumatic motor normally operating to hold the valve to close the transmission tube to outside air and'actuated by a fluctuation of pressure in the chamber to open the valve to admit outside air to the transmission tube to propel the carrier inserted in the mouth of the tube.

2. In pneumatic despatch tube apparatus, a carrier transmission tube provided with a mouth to receive carriers and to admit'outside air, a valve, the opening of which is aided, in part at least, by the pressure of said outsideair, said valve being located in the transmission tube adjacent to its mouth to control the admission of outside air to the tube, 'means' for exhausting air from the transmission tube, a chamber communicating directly with "the transmission tube inside of the valve so that the pressure in the chamber will vary with the pressure in the tube, means for causing a momentary variation of pressure in the tube to cause a fluctuation of pressure in the chamber, and a pneumatic motor normally operating to hold the valve to close the transmission tube tov outside air and actuated by a fluctuation of pressure in the chamber to open the valve to admit outside air to the. transmission tube to propel the carrier inserted in the mouth of the tube.

3. In pneumatic despatch tube apparatus,

chamber will vary with the pressure in the tube, means for causing a fluctuation of pressure in the chamber, said last mentioned means including a valve, actuation of which, unaided by other movable parts, causes said fluctuation, a pneumatic motor, freely operable by said fluctuation of pressure and normally operating to hold the main valve to close the transmission tube to outside air and actuated by a fluctuation of pressure in the chamber to open the main valve to admit outside air to the transmission tube to propel the carrier inserted in the mouth of the tube, and means for regulating thereturn movement of the motor to time the closing of the main valve to the period required for the transit oi? the carrier through the tube.

4. In pneumatic despatch tube apparatus, a carrier transmission tube provided with a mouth to receive carriers and to admit outside air, a valve located in the transmission tube adjacent to its mouth to control the admission of outside air, means for exhausting air from the t'ansmission tube, a chamber communicating directly with the transmission tube inside of the valve so that the pressure in the chamber will vary with the pressure in the tube, means for causing a fluctuation of pressure in the chamber, a pneumatic motor actuated by the (litterenee of pressure between the external air and the air in the chamber, said motor normally operating to hold the valve to close the transmission tube to outside air and actuated by a fluctuation of pressure in the chamber to open the valve to admit outside air to the transmission tube to propel the carrier inserted in the mouth of the tube, and means for restricting a too tree admission of air to said tube, for insuring a proper closure of said valve by said motor.

5. in pneumatic despatch tube apparatus, a carrier transmission tube provided with a mouth to receive carriers and to admit outside air, a valve located in the transmission tube adjacent to its mouth to control the admission of outside air to the tube, means for exhausting air from the transmission tube, a chamber communicating directly with the transmission tube inside of the valve so that the pressure in the chamber will vary with the pressure in the tube, said chamber being provided with a sub-inlet to the outside air, a pneumatic motor operated by the dijltercncc between the outside air pressure and the air pressure in the chamber, said motor being normally influenced by the outside air pressure to hold the valve to close the transmission tube to the outside air, an auxiliary valve normally closing the sub-inlet of the chamber, adapted to be momentarily opened to admit outside air to the chamber to cause a fluctuation of pressure in the chamber to cause the motor to operate to open the valve in the transmission tube to admit outside air to the tube to propel the carrier inserted in the mouth oi. the tube, means for restricting a too free admission of air to said tube, and connections, between said last mentioned means and said auxiliary valve, for effecting a movement of one by a movement of the other of these parts.

6. In pneumatic despatch tube apparatus, a carrier transmission tube provided with a mouth to receive carriers and to admit outside air, a valve located in the transmission tube adjacent to its mouth to control the admission of outside air to the tube, means for exhausting air from the transmission tube, a chamber con'nnunicating directly with the transmission tube inside of the valve so that the pressure in the chamber will vary with the pressure in the tube, means for causing a fluctuation of pressure in the chamber, a pneumatic motor normally operating to hold the valve to close the transmission tube to outside air and actuated by a fluctuation of pressure in the chamber to open the valve to admit outsidi air to the transmission tube to propel the carrier inserted in the mouth of the tube, and a rcstrictor mounted in the mouth oi the transmission tube outside of the controllingvalve operating to partly close the mouth utter the starting of a car rier and while the inner valve is open to retard the ingress oi. air into the tube to maintain in the chamber a sull'iciently partial vacuum to operate the pneumatic motor.

In testimony whereof, I have signed my name to this specification in the presence of two subscribing witnesses, this 13th day of August A. D. 1908.

ALBERT W. PEARSALL. Witnesses:

A. L. NUssU, M. '1. Goonnnn.

Copies of this patent may be obtained for five cents each, by addressing the Commissioner of Patents, Washington, I). C. 

